Recent converging evidence indicates that neurodegenerative diseases, including Alzheimer's and Parkinson's disease, are present a decade or more prior to the onset of clinical symptoms. This preclinical period is thought to be more amenable to therapeutic intervention. Detection of individuals and means to follow progression of neurodegenerative disease are major impediments to the development of therapies for this preclinical period. The olfactory neural system is vulnerable to these disease pathologies and a functional screen of smell identification (e.g, the University of Pennsylvania Smell Identification Test (UPSIT)) has been shown to be abnormal in individuals with dementia and mild cognitive impairment. However, concerns over specificity (other reasons to have an olfactory deficit) have precluded broad adoption of these methodologies. The validation of indices to identify cognitively healthy individuals at risk for developing the progressive memory symptoms of neurodegenerative diseases, and to follow these individuals over time is essential for conducting therapeutic trials in this preclinical phase.
There are numerous systems and methods for trying to diagnose neurodegenerative diseases, including countless imaging techniques, field tests for memory and motor skills, etc. All are plagued by subjective evaluation criteria and inherent limitations on the “maturity” required of the neurodegenerative disease before a diagnosis can be made. Of course, it is well documented that the long-term prognosis and quality of life is increased greatly the earlier that the diagnosis can be made. Of course, early detection in all these systems and methods stands in direct opposition to the certainty of diagnosis. As such, much better systems and methods are needed.